Orion Star A221 pH Portable Meter

  • Mid Range pH Applications pH measurement range from -2.000 to 20.000
  • Non-Volatile Memory Memory capacity to store up to 1000 time and date stamped readings
  • Easy to Use Features a large, easy to read LCD display and screen prompts
  • Warranty A221 is covered by a 3 year meter replacement warranty
Product Options


The Thermo Scientific Handheld Orion Star A221 pH Portable Meter allows you to get the readings you want wherever you need to get them. It's waterproof and protected with an IP67 rated housing making it truely portable.

The handheld A221 is easy to use and features a large, graphic LCD display with backlight which displays pH/mV/RmV and temperature along with the time, electrode status and calibration points. Its plain language screen prompts, soft keys which update for easy selection and a multi-language interface means anyone can use this meter.

To avoid missing a reading, the AUTO-READ™ function locks in the stable reading on the display and the ready indicator alerts. It can also provide up to 5 point pH calibration with automatic recognition for USE/NIST and DIN buffers.

Up to 1000 data points with time and date stamp can be held by the A221s non-volatile memory. The data gathered can be easily transferred using the with the USB and RS232 ports and complimentary data analysis software. The same ports and software can also be used to update the meter software.

The portable A221 pH Meter is powered by four AA batteries which provide 800 hours of operation. A universal power adapter is also available to use AC power.

The A221 meter comes with a 3 year meter replacement warranty.

Manufactured by: Thermo Scientific
Model: Orion Star A221 pH Portable Meter

Services offered for this product

  • Sales
  • Rental
  • Installation
  • Calibration
  • Maintenance


Mid range pH monitoring
ORP testing


Range -2.000 to 20.000
Resolution 0.1, 0.01, 0.001
Relative accuracy ±0.002
Calibration points Up to 5
Range ±2000.0 mV
Resolution 0.1
Relative accuracy ±0.2 mV or ±0.05% of reading whichever is greater
EH ORP mode Yes
Range -5 to 105°C, 23 to 221°F
Resolution 0.1
Relative accuracy ±0.1
Offset calibration 1 point
Number of points 1000 with time and date stamp
Log function Manual, automatic with AUTO-READ™
Log edit Delete last reading or all
pH electrode BNC, reference pin
ATC probe 8-pin mini-DIN
Output RS232, USB
AC adapter Optional - universal, 100-240 VAC
Battery power Included - 4 AAs
Battery life 800 hrs


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